Abstract: When an emergency button 8a of a radio communication apparatus has been turned ON and a transmit mode button 8b has been depressed, an MCU 11 sets frequencies of a receiving section 2 and a transmitting section 3 to an emergency communication frequency. The MCU 11 also causes an indicator lamp 10 to illuminate or flash at peak intensity, and causes a burst sound to be supplied from a loudspeaker 6 at the maximum volume. Then, the MCU 11 causes a built-in timer to measure a given time period while resetting the timer whenever a reception/transmission switching operation is performed or a communicating signal is detected. While the timer measures the time period, the MCU 11 causes the indicator lamp 10 to be turned off. When a timer expiration is detected, the MCU 11 causes the indicator lamp 10 to be turned on or flashed again.

Abstract: An MCU 30 of a multi-band receiver detects signal input levels from level detection circuits 18 and 18? of receiver circuits 4a and 4b, respectively, and thereby determines and identifies to which frequency band a signal input has been performed or whether simultaneous signal inputs to frequency bands have been performed. The MCU 30 controls over drive circuits for LEDs 41g and 41r according to the signal input statuses, thereby causing a multi-colored light-emitting indicator 41 to illuminate in different colors. Further, in a single signal input, the illumination color of the multi-colored light-emitting indicator 41 can be changed within an identical color group according to the level of a received frequency, for display. Further, when the received frequency is the frequency stored in a memory channel, the illumination color can be made to be different from the colors emitted in the single signal input status.

Abstract: An MCU 30 of a multi-band receiver detects signal input levels from level detection circuits 18 and 18′ of receiver circuits 4a and 4b, respectively, and thereby determines and identifies to which frequency band a signal input has been performed or whether simultaneous signal inputs to frequency bands have been performed.

Abstract: When an emergency button 8a of a radio communication apparatus has been turned ON and a transmit mode button 8b has been depressed, an MCU 11 sets frequencies of a receiving section 2 and a transmitting section 3 to an emergency communication frequency. The MCU 11 also causes an indicator lamp 10 to illuminate or flash at peak intensity, and causes a burst sound to be supplied from a loudspeaker 6 at the maximum volume.

Abstract: A radio communication apparatus has a switch for indicating occurrence of emergency, a speaker, a speaker driver for emitting an alarm sound by driving said speaker in response to the operation of the switch, and a transmitter for transmitting a predetermined alarm signal by radio. When an emergency condition occurs to an owner of the radio communication apparatus, the radio communication apparatus emits an alarm sound from the speaker and emits an alarm signal by radio in response to a switching operation. Therefore, a person a short-distance away will be informed of an emergency by sound, and a person a long-distance away will be received by using a radio.

Abstract: A key matrix circuit has a switching circuit with a first terminal and a second terminal that are switched on and off by pressing a selection key of a plurality of selection keys arranged in an N-row-by-M-column matrix, thereby making connection to a common ground circuit when a selection key is pressed. The key matrix circuit has a first voltage-dividing circuit connected between a connection circuit that connects the first terminals of the first row and a fixed power supply voltage, and a second voltage-dividing circuit connected between a connection circuit that connects the second terminals of the first column and the fixed power supply voltage, the connection points between resistances to of the first voltage-dividing circuit being connected to the connection circuits connected to the first terminals of the other rows, and the connection points between resistances of the second voltage-dividing circuit being connected to the connection circuits of the other rows.

Abstract: A radio communication apparatus has a switch for indicating occurrence of emergency, a speaker, a speaker driver for emitting an alarm sound by driving said speaker in response to the operation of the switch, and a transmitter for transmitting a predetermined alarm signal by radio. When an emergency condition occurs to an owner of the radio communication apparatus, the radio communication apparatus emits an alarm sound from the speaker and emits an alarm signal by radio in response to a switching operation. Therefore, a person a short-distance away will be informed of an emergency by sound, and a person a long-distance away will be received by using a radio.

Abstract: An electronic device (21) switches its operation mode in accordance with the type of an installed battery pack (22). The battery pack (22) has a regulator (222), a specification-discriminating terminal (TJ), and a resistor (224), connected between the regulator (222) and the specification-discriminating terminal (TJ) and having a resistance corresponding to the specification of the incorporated battery (221). The electronic device (21) has a monitor resistor (214) connected between a terminal (TL) connected to the specification-discriminating terminal (TJ) of the battery pack (22) and ground, a discriminating circuit (212, 215, 216) for detecting a monitor voltage generated across this monitor resistor (214) to discriminate the specification of the battery (221), and a switch controller (212, 219) for switching the operation mode in accordance with the specification discriminated by the discriminating circuit (212, 215, 216).